Dunaliella parva can thrive and adapt to salt stress over a wide range of NaCl concentrations which also is related to carotenoid accumulation in Dunaliella. Dunaliella parva can accumulate carotenoids; however, the underlying mechanism of carotenoid accumulation needs further research. Thus, it is necessary to study biosynthesis and regulation of carotenoids for understanding carotenoid accumulation. In the present study, a gene encoding geranylgeranyl diphosphate synthase (GGPS) from the halophilic green alga D. parva has been cloned and analyzed. It is in the branch of terpene metabolism and named as DpGGPS (D. parva GGPS). The full-length complementary DNA (cDNA) of DpGGPS was 1612 bp, including an open reading frame (ORF) of 1059 bp, 189 bp 5'-untranslated region (5'-UTR) and 364 bp 3'-UTR. The 5'-flanking region was obtained by the genome walking method. Potential regulatory elements, associated with hormones, defense, and stress, were found in the 1310 bp 5'-flanking region. Functional characterization of DpGGPS in E. coli BL21(DE3) demonstrated that DpGGPS encoded a functional GGPS. Analysis of DpGGPS expression revealed a correlation between GGPS expression and the shift of NaCl concentration, which indicated that GGPS could be a salt stress responsive gene. Cloning and expression analysis of GGPS provides a foundation for studying the regulatory mechanism of carotenoid biosynthesis, adaptation mechanism to salt stress, and massive accumulation of carotenoids in D. parva.